Login Form as service (behavior via event callbacks)

ComponentFactory.php

<?php

namespace Clevispace;

use Nette\DI;


class ComponentFactory extends DI\Container
{

	/**
	 * @param  \Nette\DI\Container
	 */
	public function __construct(DI\Container $context)
	{
		$this->context = $context;
	}



	public function createLoginForm()
	{
		return new Forms\LoginForm($this->context->user);
	}

}

LoginForm.php

<?php

namespace Clevispace\Forms;

use InvalidArgumentException;
use Nette\ComponentModel\IContainer;
use Nette\Application\UI;
use Nette\Http\User;
use Nette\Security\AuthenticationException;


/**
 * Authentication form
 * 
 * Register as service:
 * <code>
 * common:
 *     services:
 *         components:
 *             class: Clevispace\ComponentFactory
 *             arguments: [@container]
 * </code>
 * 
 * And prepare as component in presenter:
 * <code>
 * protected function createComponentLoginForm()
 * {
 *     $form = $this->context->components->createLoginForm();
 *     $form->onAuthenticationSuccess[] = callback( ... );
 *     $form->onAuthenticationFail[] = callback( ... );
 *     return $form;
 * }
 * </code>
 *
 * @author Vojtech Dobes
 */
class LoginForm extends UI\Form
{

	/** @var \Nette\Http\User */
	private $user;

	/** @var array callback() */
	public $onAuthenticationSuccess;

	/** @var array callback(AuthenticationException $e, LoginForm $form) */
	public $onAuthenticationFail;

	/** @var string */
	private $usernameField = 'username';

	/** @var string */
	private $passwordField = 'password';



	/**
	 * @param  \Nette\Http\User
	 * @param  array
	 */
	public function __construct(User $user, $params = array())
	{
		parent::__construct();
		$this->user = $user;
		if (count($params) > 2 || (count($params) > 0 && (!isset($params['usernameField']) || !isset($params['passwordField'])))) {
			throw new InvalidArgumentException("Provided params for LoginForm can be only 'usernameField' or 'passwordField'.");
		} else {
			if (isset($params['usernameField'])) {
				$this->usernameField = $params['usernameField'];
			}
			if (isset($params['passwordField'])) {
				$this->passwordField = $params['passwordField'];
			}
		}
	}



	/**
	 * Builds form
	 *
	 * @param  \Nette\Application\UI\Presenter
	 */
	public function attached($parent)
	{
		if (!$parent instanceof UI\Presenter) {
			throw InvalidStateException("LoginForm must be attached to Presenter.");
		}
		parent::attached($parent);
		$this->addText($this->usernameField, 'Username')
			->addRule($this::FILLED, 'Please fill %label.');
		$this->addPassword($this->passwordField, 'Password')
			->addRule($this::FILLED, 'Please fill %label.');
		$this->addSubmit('send', 'Login');
		$this->onSuccess[] = array($this, 'callOnSuccess');
	}



	/**
	 * Sets name of username field
	 *
	 * @param  string
	 * @return provides a fluent interface
	 */
	public function setUsernameField($field)
	{
		$this->usernameField = $field;
	}



	/**
	 * Sets name of password field
	 *
	 * @param  string
	 * @return provides a fluent interface
	 */
	public function setPasswordField($field)
	{
		$this->passwordField = $field;
		return $this;
	}



	/**
	 * @param  \Clevispace\Forms\LoginForm
	 */
	public function callOnSuccess(LoginForm $form)
	{
		$values = $this->getValues();

		try {
			$this->user->login($values[$this->usernameField], $values[$this->passwordField]);
			$this->onAuthenticationSuccess($form);
		} catch (AuthenticationException $e) {
			if (!count($this->onAuthenticationFail)) {
				throw $e;
			} else {
				$this->onAuthenticationFail($e, $this);
			}
		}
	}

}

Form as a service is bullshit... better create instance in Presenter or prepare some factory class / inherit DIContainer.